The bodhi in the center of the northern Sri Lankan town of Anuradhapura is not just any old tree. It's the old tree—the oldest historically authenticated tree in the world. Grown from a cutting of the bodhi in northern India under which Buddha gained enlightenment (that tree burned down long ago), its giant branches have cast cool shade for more than 2,000 years. But its significance is not limited to its great age. Standing at the heart of the ancient royal capital, a place that remains Sri Lanka's spiritual center today, Sri Maha Bodhi ("the Sacred Bo Tree") is regarded as the seed from which both the Sri Lankan nation and the Theravada school of Buddhism grew. Thousands of pilgrims descend during the full-moon festivals each May and June to celebrate Buddha's birth and enlightenment. But the essence of the bodhi, and of the ruins surrounding it, is serenity. No one can promise you Nirvana if you sit under its branches—but as a place to rest, in between looking at palaces and stupas, it's sublime.